[clang][dataflow] Use `Strict` accessors in comma operator and no-op cast.

[mboehme]

Summary

This patch is part of the ongoing migration to strict handling of value
categories (see https://discourse.llvm.org/t/70086 for details).

Depends On D150775

clang/lib/Analysis/FlowSensitive/Transfer.cpp

case BO_EQ: {
       auto &LHSEqRHSValue = evaluateBooleanEquality(*LHS, *RHS, Env);
       auto &Loc = Env.createStorageLocation(*S);
       Env.setStorageLocation(*S, Loc);
       Env.setValue(Loc, S->getOpcode() == BO_EQ ? LHSEqRHSValue
                                                 : Env.makeNot(LHSEqRHSValue));
       break;
     }
     case BO_Comma: {
-      if (auto *Loc = Env.getStorageLocation(*RHS, SkipPast::None))
-        Env.setStorageLocation(*S, *Loc);
+      propagateValueOrStorageLocation(*RHS, *S, Env);
       break;
     }
     default:
       break;
     }
   }
 
   void VisitDeclRefExpr(const DeclRefExpr *S) {
case CK_IntegralCast:
       // value.
     case CK_UncheckedDerivedToBase:
     case CK_ConstructorConversion:
     case CK_UserDefinedConversion:
       // FIXME: Add tests that excercise CK_UncheckedDerivedToBase,
       // CK_ConstructorConversion, and CK_UserDefinedConversion.
     case CK_NoOp: {
       // FIXME: Consider making `Environment::getStorageLocation` skip noop
-      // expressions (this and other similar expressions in the file) instead of
-      // assigning them storage locations.
-      auto *SubExprLoc = Env.getStorageLocation(*SubExpr, SkipPast::None);
-      if (SubExprLoc == nullptr)
-        break;
-
-      Env.setStorageLocation(*S, *SubExprLoc);
+      // expressions (this and other similar expressions in the file) instead
+      // of assigning them storage locations.
+      propagateValueOrStorageLocation(*SubExpr, *S, Env);
       break;
     }
     case CK_NullToPointer:
     case CK_NullToMemberPointer: {
       auto &Loc = Env.createStorageLocation(S->getType());
       Env.setStorageLocation(*S, Loc);
 
       auto &NullPointerVal =